Difficult one - we have just booked flights for May half term but no accom yet as I can't decide about the offer. I think prices are increasing next year on the whole.
HNY will be closing for refurb at some point, not sure when but it could well be next year sometime - nothing announced yet.
Check out the Irish site as I believe their prices are better for this offer - were for me anyway. As for a h/b offer - most is usually 30% off with h/b sometimes 20/25% off. I am a shareholder and will be getting APs so not sure hb would work for us so I'd rather have more money off but everyone is different. There has been the odd flash sale with 50% off on the French site recently (which can often have the best prices!), but atm their dates don't go up to that, and flash sales are shortlived as you will know. The sale a few weeks ago on the French site did not include May half term dates.